ELISA standard curve calculation question - (May/10/2011 )

Hi all. I am working with bovine hsp70 data from an ELISA however no bovine hsp70 standard was available so a human hsp70 standard was used to produce a standard curve. Can anyone tell me how to quantify levels of bovine hsp70 from optical density data using a human hsp70 standard. I have been told the data needs to be logit transformed, something about parallelism and the results will be expressed at human hsp70 equivalents. All sounds like magic to me so please help if you can.

-aquaguide-

First, take into account that your results could be seriously skewed if your anti-bovine antibody has a different affinity for human HSP70. Then, species don't matter for your standard curve; you will assume that human hsp concentrations reflect bovine . If your curve is linear, just use linear regression and figure x from the regression equation (easy in excel); If the curve is non linear, I use sigma plot to fit a curve that fits well with the standard curve data, and get SP to show the actual values of the fitted curve. Then I match each experimental value (OD=y) to the closest number in the curve to find x=concentration. It's simple interpolation. Online you'll also find how to fit a 4-parameter logistic regression in excel.